29kWh per day! 4 bed semi, no immersion, gas heating. Where's it all going? - SOLVED

A couple of weeks ago I asked this group for help and everyone was super-helpful, so I figured I’d make another post explaining what I learned in case it’s useful for anyone in the future.

I figured that I should be using closer to 12kWh per day and despite having an Octopus Mini, which let me see watts used at any given moment, I couldn’t figure out why I kept spiking to 2000 Watts and above.

Some people felt that 20kWh per day was fine. Most people said it was too much. In truth, it was less about the cost that was bugging me and more that I couldn’t figure out what was happening.

I tried flipping breakers and measuring results, but the problem with that method is that it doesn’t do a good job of capturing intermittent spikes. I was carefully turning breakers on one by one in half hour intervals, but if the spike didn’t happen in that half hour interval then I couldn’t identify it.

The most helpful comment was from /u/parsi who suggested that I use Home Assistant, combined with the Octopus plugin, then look at a chart of current consumption where I could clearly see things turning on and off again. Then, by using plugs with power monitoring, I could feed them into the same Home Assistant chart and start figuring out which device was causing the consumption. It looks like this.

As a few people said, the thing that would be causing the power use would be heating of one kind or another. We didn’t have an immersion heater connected, but I completely forgot about some underfloor heating in the en-suite which was using about 1000W for about half the day. £3 per day! On top of that I had two panel heaters, which weren’t coming on too often but when they were on at the same time as the underfloor heating I could get up above 2500W. I had two dehumidifiers which were about 300W each too. It was the fact that these were coming on and off at different times that made it so hard to track, and why the chart with individual overlays helped.

The other thing that used a ton of electricity was the hob and ovens. I didn’t realise that they’ll use around 2000W each when they’re on, which explains why the Christmas period was so high.

Beyond that I learned that my networking and NAS takes a steady 100W, the modem takes 17W, and at some point I’ll figure out what else is being used when the house is in idle mode.

Overall it’s made me think a lot about heating. Things that heat (immersion, kettles, panel heaters, ovens) gobble up watts like nothing else. It was about 90% of my electricity cost. It’s sent me down a heat pump rabbithole, because I think it will allow me to turn off the electric heating devices that are trying to compensate for the inability for my gas central heating to warm all the rooms.

Anyway, thanks a ton to everyone who gave tips and advice. Super helpful. Original post here.